LONDON — People getting cosmetic surgery in India have brought back to Britain a new gene that allows any bacteria to become a superbug, and scientists are warning this type of drug resistance could soon appear worldwide.

Rates of women who are opting for preventive mastectomies, such as Angeline Jolie, have increased by an estimated 50 percent in recent years, experts say. But many doctors are puzzled because the operation doesn't carry a 100 percent guarantee, it's major surgery -- and women have other options, from a once-a-day pill to careful monitoring.

Though already widespread in India, the new superbug gene is being increasingly spotted in Britain and elsewhere. Experts warn the booming medical tourism industries in India and Pakistan could fuel a surge in antibiotic resistance, as patients import dangerous bugs to their home countries.

The superbug gene, which can be swapped between different bacteria to make them resistant to most drugs, has so far been identified in 37 people who returned to the U.K. after undergoing surgery in India or Pakistan.

The resistant gene has also been detected in Australia, Canada, the U.S., the Netherlands and Sweden. The researchers say since many Americans and Europeans travel to India and Pakistan for elective procedures like cosmetic surgery, it was likely the superbug gene would spread worldwide.

In an article published online Wednesday in the journal Lancet Infectious Diseases, doctors reported finding a new gene, called NDM-1. The gene alters bacteria, making them resistant to nearly all known antibiotics. It has been seen largely in E. coli bacteria, the most common cause of urinary tract infections, and on DNA structures that can be easily copied and passed onto other types of bacteria.

The researchers said the superbug gene appeared to be already circulating widely in India, where the health system is much less likely to identify its presence or have adequate antibiotics to treat patients.

"The potential of NDM-1 to be a worldwide public health problem is great, and coordinated international surveillance is needed," the authors wrote.

Still, the numbers of people who have been identified with the superbug gene remains very small.

"We are potentially at the beginning of another wave of antibiotic resistance, though we still have the power to stop it," said Christopher Thomas, a professor of molecular genetics at the University of Birmingham who was not linked to the study. Thomas said better surveillance and infection control procedures might halt the gene's spread.

Thomas said while people checking into British hospitals were unlikely to encounter the superbug gene, they should remain vigilant about standard hygiene measures like properly washing their hands.

"The spread of these multi-resistant bacteria merits very close monitoring," wrote Johann Pitout of the division of microbiology at the University of Calgary, Canada, in an accompanying Lancet commentary.

Pitout called for international surveillance of the bacteria, particularly in countries that actively promote medical tourism.

"The consequences will be serious if family doctors have to treat infections caused by these multi-resistant bacteria on a daily basis," he wrote.

Almost as soon as the first antibiotic penicillin was introduced in the 1940s, bacteria began to develop resistance to its effects, prompting researchers to develop many new generations of antibiotics.

But their overuse and misuse have helped fuel the rise of drug-resistant "superbug" infections like methicillin-resistant Staphyloccus aureus (MRSA).

'Cinderella business'
For many years, antibiotic research has been a "Cinderella" sector of the pharmaceuticals industry, reflecting a mismatch between the scientific difficulty of finding treatments and the modest sales such products are likely to generate, since new drugs are typically saved only for the sickest patients.

But the increasing threat from superbugs is encouraging a rethink at the few large drugmakers still actively hunting for new antibiotics, including Pfizer, Merck, AstraZeneca, GlaxoSmithKline and Novartis.

Walsh and his international team collected bacteria samples from hospital patients in two places in India, Chennai and Haryana, and from patients referred to Britain's national reference laboratory between 2007 and 2009.

They found 44 NDM-1-positive bacteria in Chennai, 26 in Haryana, 37 in Britain, and 73 in other sites in Bangladesh, India, and Pakistan. Several of the British NDM-1 positive patients had recently traveled to India or Pakistan for hospital treatment, including cosmetic surgery, they said.

Most worryingly, NDM-1-producing bacteria are resistant to many antibiotics including carbapenems, the scientists said, a class of the drugs often reserved for emergency use and to treat infections caused by other multi-resistant bugs like MRSA and C-Difficile.

Anders Ekblom, global head of medicines development at AstraZeneca, whose Merrem antibiotic is the leading carbapenem, said he saw "great value" in investing in new antibiotics.

"We've long recognized the growing need for new antibiotics, he said. "Bacteria are continually developing resistance to our arsenal of antibiotics and NDM1 is just the latest example."